Postage meter systems print indicia and other information on mailpieces such as envelopes. The indicia represents evidence of postage payment for the mailpiece. Different countries have different systems of payment for printed indicia. The payment may be made prior to when the imprint is made, with the prepaid postage value being deducted from the value stored in the postage meter system. Alternatively, payment may be made subsequent to when the imprint is made, based on the various indicia that had been printed. Postal processing equipment scans the face of mail pieces and decodes the data (e.g., barcodes) printed on the mail piece. The data in an indicium provides proof that a specific postage amount was paid. The quality of the print of a postal indicium is the primary factor that determines whether or not postal equipment which scans and images the mail piece can decode the data in the indicium. Therefore, achieving high print quality is critical to ensuring the security of postal funds. Postal services have established quality standards for the indicia image printed on mailpieces. Accordingly, standards have been promulgated by postal services for the quality of the indicia imprint. An example of such standard is set forth International Standard ISO/IEC 18050: Print Quality Attributes for Machine Readable Digital Postage Marks.
In processing mail, when indicia or another imprint on a mailpiece fails to meet the required standard, the mail may be processed in other than the standard manner. When inferior quality inks or ink cartridges are used in postage meter systems, the consequence can be significant and can be more than merely poor images and the failure of proper processing in the post office. It can also involve the loss of funds, the undeliverability of mail and damage to the equipment (e.g., a postage meter) itself. The inferior quality ink may damage the print head of a meter system by permanently clogging or pitting the print head nozzles that are employed to print indicia and other information. This may require that the print head be replaced. Moreover, the mail itself may be returned by the postal service to the sender, causing additional expense and delay in processing the mail. Since postage meter systems are used frequently in high-volume production of mail, the failure to make proper imprints can impact large amounts of mailpieces and have significant commercial consequence to the mailer.
To help avoid printing problems, postage meter manufacturers carefully develop and formulate ink used in postage meter systems. This is to ensure that the inks and ink systems meet the requirements of the specific countries where the postage meter systems are employed. Postage meter manufacturers implement extensive testing, specific formulation and quality assurance programs in the manufacture and storage of postage meter inks. It is, thus, desirable to ensure the proper performance of postage meter systems under various operating conditions, including where improper or inferior quality ink may be employed.